1. Field of the Invention
The disclosed invention provides an apparatus for the storage of filmstrip material, especially suitable for endless loop applications.
2. Prior Art
The traditional manner for storage of filmstrip materials is in a reel, where the film is wound about itself so that each layer of the film contacts the layers above and below it. Such a film storage method is utilized in many applications, e.q., magnetic film reels such as cassettes or cartridges, movie film reels, etc. It is the traditional method for storing lengths of filmstrips. The advantage that such a storage method has is that the apparatus required to create such a reel of film is easily supplied.
There are two principal disadvantages to such film storage techniques. First, each layer of the film is in full contact across the entire width of the film with adjacent layers of the filmstrip. If the filmstrip contains information which can be altered or obliterated by dust or other materials caught between the layers of the wound filmstrip, such storage techniques require special consideration be given to maintain the cleanliness of the filmstrip in order to preserve the information on the filmstrip. Second, certain applications require the film to be continuously played. These applications, commonly referred to as "endless loop" applications, require special apparatus for the continuous circulation of the filmstrip.
Endless loop reel apparatus can be divided into two broad classifications. The first is one, such as the "8-track" magnetic film cartridge used for automobile sound playback, in which the magnetic film is formed into a loosely wound reel. The film is so loosely wound that it can be spooled on the outside of the reel and removed from the hub of the reel in a continuous manner. Unfortunately such types of endless loop apparatus requires a specially treated filmstrip which is able to easily slide across itself as it is loosely coiled. Special lubricants are used in the filmstrip material to allow this. When the lubricants loose their effectiveness, either by drying up or by being physically removed by use of the filmstrip, the apparatus turns into a self-destruct mechanism for the enclosed filmstrip material due to the binding of the layers of the film.
The second traditional method for providing filmstrips in an endless loop type application is for the providing of two reels for the storage of the film. By appropriate threading of the film, it is possible to create a film path such that initially the entire filmstrip is stored on one reel, and is transported across the projector, recorder, or other filmstrip utilization device to the other reel. The reel apparatus must allow for the feeding of the filmstrip from either of the reel assemblies since the film is moved from one reel to the other and back to the first reel again. This type of apparatus requires two reel assemblies, each sufficiently large to contain the entire filmstrip. Where a considerable amount of film is utilized, the floor space involved in providing for storage space for the two reel assemblies is considerable. In addition, such apparatus requires considerable mechanical complexity due to the complicated threading of the film and to the sophisticated methods for creating appropriately formed film reels.
It is an objective of the herein disclosed invention to provide a method for storing endless loop filmstrips in which a minimum amount of floor space is required, and in which a gentle storage method is provided, causing the filmstrip to minimally contact itself, thereby reducing the potential for injury to the filmstrip. It is a further objective to provide a method for automatic adjustment of the feeding of the filmstrip suitable for a variety of film speeds.